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From: Peter Zijlstra <peterz@infradead.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
	Oleg Nesterov <oleg@redhat.com>,
	andrii@kernel.org, mhiramat@kernel.org, jolsa@kernel.org,
	rostedt@goodmis.org, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH v4 0/9] uprobes: misc cleanups/simplifications
Date: Fri, 2 Aug 2024 11:25:28 +0200	[thread overview]
Message-ID: <20240802092528.GF39708@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAEf4BzY9diEi2_tHsLxB4Yk-ZAWHT=XJNmagjQtOXc7qShqgrA@mail.gmail.com>

On Thu, Aug 01, 2024 at 02:13:41PM -0700, Andrii Nakryiko wrote:

> Ok, this bisected to:
> 
> 675ad74989c2 ("perf/core: Add aux_pause, aux_resume, aux_start_paused")

Adrian, there are at least two obvious bugs there:

 - aux_action was key's off of PERF_PMU_CAP_AUX_OUTPUT, which is not
   right, that's the capability where events can output to AUX -- aka.
   PEBS-to-PT. It should be PERF_PMU_CAP_ITRACE, which is the
   PT/CoreSight thing.

 - it sets aux_paused unconditionally, which is scribbling in the giant
   union which is overwriting state set by perf_init_event().

But I think there's more problems, we need to do the aux_action
validation after perf_get_aux_event(), we can't know if having those
bits set makes sense before that. This means the perf_event_alloc() site
is wrong in the first place.

I'm going to drop these patches for now. Please rework.

  parent reply	other threads:[~2024-08-02  9:25 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-01 13:26 [PATCH v4 0/9] uprobes: misc cleanups/simplifications Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 1/9] uprobes: document the usage of mm->mmap_lock Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 2/9] uprobes: is_trap_at_addr: don't use get_user_pages_remote() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 3/9] uprobes: simplify error handling for alloc_uprobe() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Andrii Nakryiko
2024-08-01 13:27 ` [PATCH v4 4/9] selftests/bpf: fix uprobe.path leak in bpf_testmod Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Jiri Olsa
2024-08-01 13:27 ` [PATCH v4 5/9] uprobes: kill uprobe_register_refctr() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 6/9] uprobes: make uprobe_register() return struct uprobe * Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 7/9] uprobes: change uprobe_register() to use uprobe_unregister() instead of __uprobe_unregister() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 8/9] uprobes: fold __uprobe_unregister() into uprobe_unregister() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:27 ` [PATCH v4 9/9] uprobes: shift put_uprobe() from delete_uprobe() to uprobe_unregister() Oleg Nesterov
2024-08-05 11:56   ` [tip: perf/core] " tip-bot2 for Oleg Nesterov
2024-08-01 13:36 ` [PATCH v4 0/9] uprobes: misc cleanups/simplifications Peter Zijlstra
2024-08-01 18:58   ` Andrii Nakryiko
2024-08-01 21:13     ` Andrii Nakryiko
2024-08-02  8:27       ` Peter Zijlstra
2024-08-02  9:25       ` Peter Zijlstra [this message]
2024-08-02 11:02         ` Adrian Hunter
2024-08-02 17:14           ` Adrian Hunter

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